The present invention relates to a battery and a battery holder that can be used with a different type of battery having a different voltage as current sources for various electric devices while preventing troubles caused by misuse of battery wherein a wrong type of battery is used either alone or in combination or a battery is reversely oriented.
The battery that is most commonly used in recent years is generally of cylindrical shape as shown in FIG. 11. Most of such cylindrical batteries Ba1 are configured such that a projection formed on a sealing assembly (not shown) for sealing an open end of a cylindrical cell casing 1 at one end thereof in a lengthwise direction (axial direction) serves as a positive terminal 2 and a flat surface at the other end of the cell casing serves as a negative terminal 3. Cylindrical cell of such type is widespread and has found a variety of applications in various sizes of IEC standard AAA, AA, A, C, and D. Typically, manganese dry cell batteries and alkaline manganese dry cell batteries are available on the market and widely used in the form of such cylindrical cell Ba1 for various general purpose applications. All of these various dry cell batteries generate electricity of 1.5V, because of which they are manufactured with the same outer dimensions and in the same configuration of the cylindrical shape and sold, for the purpose of enjoying the advantage of interchangeability between different types of cylindrical cells.
Meanwhile, lithium batteries are known to have outstanding characteristics such as light weight, high voltage, high energy density, and long life, and have been mass-produced and widely used for specific purposes as current sources for liquid crystal digital watches, memory backup of electronic instruments, and automatic compact cameras. Since lithium has a poor potential of about xe2x88x923V, a lithium battery has an output voltage of 3V that is twice as high as the output voltage of the above mentioned various dry cell batteries and other aqueous electrolyte cells such as nickel cadmium cells. Specifically, a lithium battery constructed with manganese dioxide or fluorinated graphite for the positive electrode is most widely known as a 3V output voltage cell and has found wide applications.
However, the lithium battery cannot be used interchangeably with aqueous electrolyte cells because of its 3V output voltage that is twice as high as that of the aqueous electrolyte cells. That is, if a 3V lithium battery as described above and a 1.5V dry cell battery are mistakenly inserted together in an electric device which requires a rated voltage of 3V and has a configuration which is intended for receiving two series-connected aqueous electrolyte cells, and if these batteries are connected in series, it will not only deteriorate the performance of the batteries but also cause a serious trouble such as damage to or impairment of the electric device. For that reason those batteries of which output voltage is 3V such as the lithium battery have been developed in sizes and forms that are different from those of the 1.5V aqueous electrolyte batteries in order to avoid misuse.
If, for a portable electric device that needs a power source of more than 3 volts, a lithium battery can be used interchangeably with an aqueous electrolyte cell such as a dry cell, it will be very convenient since the user can use a lithium battery when he/she has no dry cells in stock. There will be another advantage that the lithium battery, that has various excellent characteristics as listed above, can be used not only for specific purposes but for a wide range of applications. In addition, a considerable decrease achieved by mass-production is expected since the existing equipment and metal molds for manufacturing aqueous electrolyte cells can be utilized for the production of lithium cells having the same outer dimensions as those of the aqueous electrolyte cells for the purpose of interchangeable use. Similarly, a decrease in cost during the distribution on the market can also be expected. To achieve such objects, a lithium battery must be realized which has a configuration and a structure such that the trouble caused by misuse wherein a wrong type of battery is used either alone or in combination or a battery is reversely oriented is reliably prevented, while having the same outer dimensions as those of the different type of battery.
A cylindrical secondary battery having a configuration that is different from that of the general cylindrical cell Ba1 shown in FIG. 11 is known as described in Japanese Laid-Open Patent Application 8-96793. As shown in FIG. 12A, this cell 4 has a projection on a sealing assembly (not shown) for sealing one open end of a metallic cell casing 10 as the positive end terminal 7 while the other end surface is electrically insulated, and two opposite, spaced negative electrode side terminals 8, 9 on the exterior surface of the cell casing 10. This secondary cell 4 is intended for interchangeable use with a primary cell that generates the same voltage as the secondary cell 4 and not for interchangeable use with a different type of battery with a different output voltage.
One of the side terminals 8 of this secondary cell 4 is given for charging purpose while the other side terminal 9 is used for detection of whether or not it is a secondary cell and for discharge to a load. The other end of the cell casing opposite the positive terminal is electrically insulated so that the secondary cell 4 is prevented from being connected in series to a primary cell that is mistakenly inserted together with the secondary cell 4 in a battery compartment. Thereby, only when either one of primary cells or secondary cells 4 are inserted in an end-to-end configuration in the battery compartment of an electric device are the cells connected in series, by which even if a primary cell without the side terminals 8, 9 is inserted mistakenly, it is prevented from being charged, and also, even if primary cells and secondary cells having the same output voltage are mixedly inserted, overdischarge of a secondary cell is prevented.
Referring to FIG. 12B which shows a production process of the above secondary cell 4, an insulation plate 13 having a projection 12 for determining the orientation of the secondary cell 4 and an insulation plate 17 having an insertion hole 14 for passing the projected positive terminal 7 therethrough are respectively bonded to the bottom and the top of an unjacketed cell that is obtained by inserting an electrode assembly into the cell casing 10, filling an electrolyte, and sealing the open end with a sealing assembly 11. A shrink-and-tack label 18 having terminal apertures 19 is then wound around and bonded to the exterior surface of the unjacketed cell, whereby the two portions of the exterior surface of the cell casing 10 corresponding to the terminal apertures 19 are left exposed as the side terminals 8, 9. The secondary cell 4 is inserted in the battery compartment with the projection 12 or the elongated, projected end terminal 7 aligned with a mark provided on the device side. When the cell is mounted, the side terminals 8, 9 situated on both sides of a width direction of the projection 12 are properly located in position where they contact charging element and detection or load element of the device side. The end terminal 7 and the projection 12, both being of elongated shape, are provided in parallel arrangement with each other as shown in the top plan view of FIG. 12C and the bottom plan view of FIG. 12D.
The structure of the above second cell 4 is, however, not suitable for manufacture in a high-speeded production line and its practicability is low, since it is necessary to align the terminal apertures 19, 19 of the shrink-and-tack label 18 and the insertion hole 14 of the upper insulation plate 13 and the projection 12 of the lower insulation plate 17 with each other, and to position the insertion hole 14 of the insulation plate 17 and the end terminal 7 in relation to each other. Moreover, the projection 12 on the bottom of the secondary cell 4 necessitates the provision of a slot for receiving the projection 12 in the battery compartment of the electric device, wherefore it is difficult to use the cell 4 interchangeably with other types of cells of the same size. In addition, it is generally believed that a battery has its terminals on both ends, and the battery user may well try to remove the insulation plate 13 inadvertently or by mistake. Since no countermeasure for such risk is provided, it is possible that the insulation plate 13 is removed even though it is relatively thick with projection 12, and that the cell is mistakenly used without the insulation plate 13.
There are known other batteries that allow for current collection and charging from the side surface, such as a secondary cell having a charging terminal on its side and a pair of discharging terminals on both ends of the cell casing, and a nickel cadmium cell of AA size that can be charged and discharged from a portion on its side. None of these cells enables interchangeable use with a different type of battery having a different voltage while preventing troubles caused by misuse or reverse polarity, and has a construction suitable for mass-production.
An object of the present invention is to provide a battery having a construction which enables mass-production and interchangeable use of the battery with a different type of battery having a different voltage and which prevents various troubles that can be caused by misuse of battery.
Another object of the present invention is to provide a common battery holder for different types of batteries having different output voltages, which battery holder is provided with a construction for preventing reliably the trouble caused by misuse or reverse polarity of battery.
In order to accomplish the above objects, the present invention provides a battery comprising a first terminal provided at one end of a battery casing, and a second terminal on an exterior surface of the battery casing. The second terminal is an entire circular circumferential surface of a predetermined width of the battery casing. The other end of the battery casing opposite the first terminal is electrically insulated by affixing an electrically nonconductive film thereto. Two heat-shrinkable nonconductive labels are wound around and bonded on the exterior surface of the battery casing at a predetermined spacing corresponding to the width of the second terminal, so that the entire exterior surface of the battery casing except a portion of the second terminal is electrically insulated by the heat-shrinkable nonconductive labels, and that the second terminal is formed in a recessed, ring-like form between the two heat-shrinkable nonconductive labels.
Since the present invention battery has its negative terminal in a recessed, ring-like form by electrically insulating the exterior surface of the battery casing with the heat-shrinkable nonconductive labels except the circular circumferential surface of predetermined width on the outer wall of the battery, the battery can be inserted into a battery holder without specifically determining its orientation. Accordingly, the construction for determining the inserting direction of the battery provided to a conventional secondary battery such as an elongated end terminal or projection are not necessary. The present invention battery can be mass-produced in a high-speeded production line and is highly practicable, since the two heat-shrinkable nonconductive labels need not be positioned in relation to each other before being bonded to the battery casing. Moreover, with the negative terminal in a recessed, ring-like form on the outer cylindrical surface of the battery casing, the present invention battery can be clearly distinguished from a different type of battery that has the terminals on both ends, while it can be used interchangeably with the different type of battery.
In another aspect of the present invention, in place of the two heat-shrinkable nonconductive labels, a sheet of heat-shrinkable nonconductive label having a separable portion at a position corresponding to the second terminal is wound around and bonded to the exterior surface of the battery casing so that the entire exterior surface of the battery casing is electrically insulated by the heat-shrinkable nonconductive label, the second terminal being covered with the separable portion of the heat-shrinkable nonconductive label before use. The separable portion of the heat-shrinkable nonconductive label is removed for revealing the second terminal when the battery is to be used.
When the battery is used, the separable portion of the heat-shrinkable nonconductive label is removed so as to expose the negative terminal. Same effects of the present invention battery as described above can be thereby achieved. In addition, since the negative terminal is covered with the label before the battery is used, its storability is excellent because of low self discharge, and its maintenance is facilitated. Moreover, the battery before use is clearly distinguishable from a used battery owing to the separable portion covering the negative terminal. There is also the advantage that both terminals are prevented from being short-circuited accidentally by a long metallic object. Furthermore, a sheet of heat-shrinkable nonconductive label can be readily wound around and bonded to the battery casing with the similar method to the one used for producing existing dry cell batteries, and thereby the bonding process of the heat-shrinkable nonconductive label can be simplified.
The heat-shrinkable nonconductive label is preliminarily coated with a heat-sensitive adhesive on an inner side thereof.
It is desirable that the negative terminal be located away from the center in a longitudinal direction of the battery casing toward one side at a distance from one end of the battery casing.
Thereby, the negative terminal of the battery which is located on one side of the center in a longitudinal direction is not connected to the side contact of the battery holder when inserted reversely, and thus the cell reverse can be prevented.
It is preferable to coat the end of the battery casing opposite the positive terminal with an electrically nonconductive material, and further to cover the end with a plurality of electrically nonconductive films superposed upon one another on said electrically nonconductive coating.
The plurality of electrically nonconductive films will deter the battery user from trying to remove the electrically nonconductive film either inadvertently or by mistake. Should the end surface of the battery casing be exposed, the existence of the nonconductive coating will help the user notice that it is not a terminal. The end of the battery casing opposite the positive terminal is thus prevented from being used as a terminal by misunderstanding.
The end of the battery casing opposite the positive terminal may be covered with a first nonconductive film of a size smaller than the end surface of the battery casing, and a second nonconductive film of a size smaller than the first nonconductive film bonded upon the first nonconductive film, said first and second nonconductive films being bonded to the end surface of the battery casing with a heat-sensitive adhesive that exhibits adhesion when heated.
In this way, two electrically nonconductive films can be smoothly superposed and bonded on one another, whereby the bonding process of multi-layer insulation structure of the electrically nonconductive films can be facilitated, and high quality batteries can be produced at low cost. The resistance to peeling of the first nonconductive film that is larger than the second nonconductive film is especially enhanced because the edge of the heat-shrinkable nonconductive label is overlapped from outside and shrunk into close contact with the periphery of the first nonconductive film, thereby preventing the edge thereof from peeling off.
The heat-shrinkable nonconductive label may have a width such that when it is wound around the exterior surface of the battery casing, one edge thereof extends a predetermined length from the ends of the battery casing, said edge of the heat-shrinkable nonconductive label being shrunk into close contact with the periphery of the ends of the battery casing.
Thereby, the edge of the heat-shrinkable nonconductive label is shrunk and fit onto the periphery of the electrically nonconductive film on the end surface of the battery casing. The resistance to peeling of the electrically nonconductive film is remarkably enhanced. The label of the present invention battery thus has an improved resistance to peeling when abraded with a foreign matter upon unexpected vibration, shock, or friction during the distribution of the battery.
The heat-shrinkable nonconductive label and the electrically nonconductive film should preferably be both opaquely colored, while the first and second terminals should have a metallic shine of nickel-plating.
The battery user who believes that a battery has its terminals on both ends can readily notice that one end surface of the present invention battery is not a terminal by the colored electrically nonconductive film, and will hardly try to remove the nonconductive film, whereby misuse of the battery can be prevented.
It is possible to construct the battery of the present invention such that both of the end surfaces of the battery casing are formed flat.
The battery casing can be elongated by the length corresponding to the projection on the sealing assembly that usually forms the positive terminal, and the battery volume is increased accordingly. The battery capacity can be thus augmented by increasing the electrode plate area of the electrode assembly in the battery.
In the battery with the heat-shrinkable label with the separable portion, the separable portion should preferably comprise rows of perforations formed along slits on both side thereof.
The separable portion of the label can thereby be easily removed so as to expose the negative terminal, without causing a portion of the label in the vicinity of the negative terminal to peel off.
The heat-shrinkable nonconductive label should preferably be coated with a heat-sensitive adhesive on an inner surface thereof except the separable portion.
The separable portion can thereby be readily removed when the battery is to be used.
The battery of the present invention may be applied to a cylindrical lithium primary cell which is configured in cylindrical form of the same outer dimensions as those of a cylindrical aqueous electrolyte battery, and is constructed with lithium for the negative electrode, and which has an output voltage higher than that of the aqueous electrolyte battery.
Thereby, the same battery casing used for the cylindrical aqueous electrolyte battery can be used for the present invention battery, and also, the equipment and metal molds for the production of existing cylindrical aqueous electrolyte batteries can be utilized, whereby high quality lithium primary batteries can be produced at a remarkably reduced cost. In addition, since the lithium primary battery according to the present invention has the same outer dimensions as those of the existing aqueous electrolyte battery, a common battery holder for the existing aqueous electrolyte battery can be used, while it is clearly distinguishable from the aqueous electrolyte battery, because of the negative terminal provided on the side surface of the battery casing and because of the end surface opposite the positive terminal being electrically insulated and having no function as a terminal, for which it cannot be used in a general electric device having a contact configuration for aqueous electrolyte batteries that have the terminals on both ends thereof. Accordingly, the lithium battery having outstanding characteristics such as light weight, high voltage, high energy density, and long life can be used not only for limited, specific purposes but for a wide range of applications, and can be used interchangeably with the aqueous electrolyte batteries.
The present invention further provides a battery holder comprising a first cavity for accommodating a first battery that has a first terminal on one end in a lengthwise direction and a second terminal on a side portion thereof, and has an output voltage of E volts, and a second cavity for accommodating a second battery that has a first terminal on one end in a longitudinal direction and a second terminal on the other end thereof, and has an output voltage of E/2 volts. The first cavity is provided with a positive contact and a negative contact at both ends thereof for contacting the first and second terminals of the second battery, and provided with a side contact on a side portion for contacting the second terminal of the first battery. The second cavity is provided with a positive contact and a negative contact at both ends thereof for contacting the first and second terminals of the second battery. The negative contact of the first cavity and the positive contact of the second cavity is connected with each other through a connector. The side contact of the first cavity and the negative contact of the second cavity is connected to and lead out as one common load terminal. The positive contact of the first cavity is lead out as the other load terminal.
The battery holder according to the present invention allows a voltage of E volts that is either the output voltage of the first battery or the sum of the output voltages of two series-connected second batteries to be supplied to the load terminals, only when the first battery is inserted in the first cavity in correct orientation, or when the two second batteries are respectively inserted in the first and second cavities in correct orientation. If, for example, the first battery is mistakenly inserted in the second cavity, it is not connected to another battery in the first cavity since the first battery has one terminal at only one end thereof, whereby it is prevented that an overvoltage is applied to the load terminals.
It is preferable that the side contact of the first cavity be situated away from the center in a longitudinal direction toward one side.
In this way, if the first battery is inserted in the first cavity reversely by mistake, the side terminal of the battery is not connected to the side contact of the first cavity, whereby cell reverse of the first battery can be prevented.
Other objects and characteristics of the present invention will become evident in the detailed descriptions and drawings given below. The characteristic features of the present invention can be used, where possible, alone, or in various multiple combinations.